<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    

    <script>
        // typeof

        var  a = 1 ;
        console.log(typeof a);

        //new Array()
        var arr = [1,2,3];
        console.log(typeof arr);

        // console.log(typeof arr === Array);  无效

        //instanceof  判断 对象属于哪个函数

        console.log(arr instanceof Array);
        


        
        
        
    </script>
</body>
</html>